• Clinical and Experimental Reproductive Medicine
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• v.12 no.2
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• pp.39-57
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• 1985

Presented in this paper the data from a chromosome study of 397 patients referred for suspected chromosmal abnormalities. Karyotypes were obtained using short-term blood culture and direct method. Of these 238 patients had normal chromosome complements; 159 (40.1%) patients had chromosome abnormality. Among all patients with chromosome abnormalities, 82.4% (131/159) had aberrations of chromosome number, the others 17.60/0 (28/159\ had aberrations of chromosome structure. Ten had a chromosome rearrangement; Five of them were reciprocal and five Robertsonian translocations. Four patients with pericentric inversions and one with paracentric inversions and four with isochromosomes were observed. There were four patients with marker chromosome, two patients had a chromosome insertion; and three others. (additional abnormal chromosomes.) Thus the results of the present study indicate the importance of cytogenetic evaluation in clinically abnormal patients.

• The Korean Journal of Zoology
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• v.29 no.3
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• pp.208-214
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• 1986

Comparative study of karyotypes in two allotypes $(Mdh-1^{MM} and Mdh-1^{MS})$ of the dark chub (Zacco temmincki) was examined. Both types had diploid number of 48 but the 7th chromosome was strikingly different between them. The chromosomes of $Mdh-1^{MM}$ type was consisted of 6 pairs of metacentrics, 6 pairs of submetacentrics, and 12 pairs of acrocentrics whereas the chromosomes of $Mdh-1^{MS}$ type had 7 pairs of metacentrics, 5 pairs of submetacentrics and 12 pairs of acrocentrics. No hybrid type between these two types was found in sympatric area at Tongchon River Namhae. Probable reproductive isolation between them was discussed.

• Journal of the Korean Society of Tobacco Science
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• v.18 no.1
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• pp.12-20
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• 1996

The spermatogenesis and chromosome number were investigated in the pupal testes of Helicouerpa assulta Guenee by light microscopy. During the spermatogenesis, each bundle of P8(256) sperms developed by 6 mitotic and 2 meiotic spermatogonial divisions. From the early stage of spermatogenesis, it was distinguishable between two kinds of sperm differentiation, eupyrene and apyrene spermatogenesis, which are characteristic in Lepidoptera, by the differences in nuclear shape and cell distribution in immature spermatocyst. Through the followed spermiogenesis, the spermatocysts were developed into two kinds of mature cyst, a streamline-shaped eupyrene cyst with nucleated sperms of thready head or a long spindle-shaped apyrene cyst with anucleated sperms of cylindrical head. As the results off chromosomal analysis at metaphase of the spermatogonial mitosis and spermatocytic meiosis, the chromosome number were 2n=6a/n=31, respectively, and no variation between individuals.

• Fisheries and Aquatic Sciences
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• v.10 no.1
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• pp.24-29
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• 2007

Our objective was to clarify the cytogenetic characteristics, including karyotypes, cellular DNA content, and nuclear size of erythrocytes, of black plaice Pleuronectes obscurus, dotted gizzard shad Konosirus punctatus, and perch sculpin Pseudoblennius percoides, collected from the coastal areas of Jo Island, Busan, Korea. Karyotypes of P. obscurus and K. punctatus both had a diploid number of 48 and a fundamental number (FN) of 48, with a chromosome formula of 48T. The karyotype of p. percoides had a diploid number of 46 and FN of 56, with a chromosome formula of 10SM +36T. No sex-associated heteromorphic pairs were detected for any species. The variation in DNA values (P. obscurus=1.15 pg/nucleus, K. punctatus=1.56pg/nucleus, P. percoides=1.11 pg/nucleus) was positively related to variation in chromosome FN.

• Molecules and Cells
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• v.37 no.10
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• pp.713-718
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• 2014

Alteration in chromosome numbers and structures instigate and foster massive genetic instability. As Boveri has seen a hundred years ago (Boveri, 1914; 2008), aneuploidy is hall-mark of many cancers. However, whether aneuploidy is the cause or the result of cancer is still at debate. The molecular mechanism behind aneuploidy includes the chromosome mis-segregation in mitosis by the compromise of spindle assembly checkpoint (SAC). SAC is an elaborate network of proteins, which monitor that all chromosomes are bipolarly attached with the spindles. Therefore, the weakening of the SAC is the major reason for chromosome number instability, while complete compromise of SAC results in detrimental death, exemplified in natural abortion in embryonic stage. Here, I will review on the recent progress on the understanding of chromosome missegregation and cancer, based on the comparison of different mouse models of BubR1, the core component of SAC.

• Korean Journal of Plant Taxonomy
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• v.50 no.3
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• pp.361-367
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• 2020

We report meiotic chromosome numbers of three taxa in Carex sect. Mitratae in Korea: Carex breviculmis R. Br. (n = 32_II, 33_II, 34_II), C. polyschoena H. Lév. & Vaniot (n = 37_II, 38_II), and C. sabynensis Less. ex Kunth (n = 27_II). Section Mitratae is one of the most species-rich Asian groups in Carex, comprising approximately 45-80 taxa. Twenty-seven of these occur in Korea, and they are some of the most challenging taxa to identify due to their obscure and inconspicuous diagnostic characters. Including the counts reported here, half of the native Korean sect. Mitratae chromosome numbers have been documented. Their haploid chromosome numbers range from n = 10 to n = 40, and many exhibit variations in the numbers counted within a taxon. These variations, along with the overall significant variation in sect. Mitratae, suggest that dynamic chromosome activity may be related to the high species diversity of Carex.

• Genomics & Informatics
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• v.13 no.4
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• pp.102-111
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• 2015

The karyotypes of most species of crocodilians were studied using conventional and molecular cytogenetics. These provided an important contribution of chromosomal rearrangements for the evolutionary processes of Crocodylia and Sauropsida (birds and reptiles). The karyotypic features of crocodilians contain small diploid chromosome numbers (30~42), with little interspecific variation of the chromosome arm number (fundamental number) among crocodiles (56~60). This suggested that centric fusion and/or fission events occurred in the lineage, leading to crocodilian evolution and diversity. The chromosome numbers of Alligator, Caiman, Melanosuchus, Paleosuchus, Gavialis, Tomistoma, Mecistops, and Osteolaemus were stable within each genus, whereas those of Crocodylus (crocodylians) varied within the taxa. This agreed with molecular phylogeny that suggested a highly recent radiation of Crocodylus species. Karyotype analysis also suggests the direction of molecular phylogenetic placement among Crocodylus species and their migration from the Indo-Pacific to Africa and The New World. Crocodylus species originated from an ancestor in the Indo-Pacific around 9~16 million years ago (MYA) in the mid-Miocene, with a rapid radiation and dispersion into Africa 8~12 MYA. This was followed by a trans-Atlantic dispersion to the New World between 4~8 MYA in the Pliocene. The chromosomes provided a better understanding of crocodilian evolution and diversity, which will be useful for further study of the genome evolution in Crocodylia.

• The Journal of the Korean Society for Microbiology
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• v.19 no.1
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• pp.85-108
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• 1984

In order to study the relationship between resistance of tumor cells to anticancer drugs and immunologic cytotoxicity and their chromosome number, a line of cancer cells (NS-1) was exposed to BCNU and CCNU in vitro. Characteristics of the distribution of chromosome number of the survived cells were then comparatively analyzed. Effect of immune mediated cytotoxicity, i.e. complement and cell-mediated cytotoxicity, on the ploidy characteristics was observed in the same way. NS-1 cells were found to be a population of neoplastic cells of heterogeneity having 5 to 115 chromosomes per cell in metaphase. The majority of the cells were belong to the class of chromosome number 56 to 60 which were considered as the stem cell line. Dramatic changes in the distribution of chromosome number following drug treatment were not observed. However the range of chromosome distribution was slightly changed. Characteristics of chromosomal distribution of drug treated cells were not significantly varied by different doses of drug treated. Changed chromosomal distribution patterns of drug treated cells were reversible, especially the cells having 56 to 60 chromosomes recovered rapidly. Cells having 41-60 and 61-80 chromosomes among cells treated with BCNU and cells with 41-60 chromosomes after CCNU treatment were the major population which regenerated continuously. Following BCNU treatment cells having 61-80 chromosomes were not varied much whereas CCNU treatment affects the population in the same class. Chromosomal aberrations were significantly enhanced by BCNU and CCNU treatment. The frequency of chromosomal aberrations was greater in cells having more than 40 chromosomes compared with that in cells having less than 40 chromosomes. Changes in ploidy characteristics of the cells following complement mediated and cell mediated cytotoxicity were not significant. Therefore it was tentatively concluded that association of numerical distribution pattern of NS-1 cells with the response to the treatment used in this experiment was not recognized.

• Korean Journal of Medicinal Crop Science
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• v.12 no.5
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• pp.397-400
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• 2004

The chromosome numbers and karyotypes were investigated in four Korean native species of the genus Hosta. The chromosome complements were diploid of 2n=60 in H. japonica var. lancifolia Nakai and H. capitata Nakai, aneuploid of 2n=59 in H. minor (Bak.) Nakai, and modified triploid of 2n=92 in H. longipes (Fr. et Sav.) Matsumura. All the species carried four sets of distinctly large chromosomes of which the chromosome types were telocentrics or subtelocentrics with $4.4{\sim}7.2\;{\mu}m$ in length. The other chromosomes were meta-, submeta, subtelo-, or telocentric types and showed gradual length degradation in the range of $1.0{\sim}3.0\;{\mu}m$. The satellites appeared vestigially in a pair or a triplet set of chromosomes which depends on the species. New chromosome number and karyotype in H. longipes were the first report in this species. The structural rearrangement was suggested to explain the modified triploid composition of 2n=92.

• The Korean Journal of Zoology
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• v.15 no.3
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• pp.95-100
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• 1972

Dose response and time dependence of unscheduled DNA synthesis induced by X-rays were measured to determine if any correlation exists between unscheduled DNA synthesis, modal chromosome number, chromosome exchange and mitotic activity in four mammalian cell strains. Unscheduled DNA synthesis occurred in all strains studied. The rate was dose-dependent and strain-specific. Only HeLa $S_3$ showed a staturated dose response after 4, 000 R, other cells were linearly proportional to dose increases. Time dependence of unscheduled DNA synthesis was completed within 2 hours after irradiation regardless of cell strains. Unscheduled DNA synthesis was not directly related to modal chromosome number, total exchange rate and mitotic activity. Mitotic activity and chromosome exchange were both dose-dependent, but the rates of them were inversely related.